Speaking of awesome MMOs, I'm going to have to throw my hat into the Ring created by the (still-upcoming) Guild Wars 2. Since the announcement of its development in 2007, the devs have worked hard to ensure that the game is not only massive in scale, but that it has the visceral 'heft' you rarely feel in other games.
For example, in other Fantasy-Flavoured MMOs, a warrior shieldbashes a random mook; the mook is stunned but doesn't really move. In GW2, a Guardian (defensive-oriented warrior, akin to a Paladin in regards to general attitude) gets a hammer attack called 'Banish'. It 'Banishes' an enemy with a vicious underhanded swing from a two-handed warhammer to send even Centaurs and larger creatures flying 20 or more feet away.
In other MMOs, you can interact with the Environment in one of a handful of ways; mining for ore, pulling levers to open gates, harvesting herbs. In GW2, you can pick up a boulder from a partly-crumbled wall, and toss it at an enemy to knock the sucker flat, or bowl him or her over and away from his buddies. (Or, if playing as an elementalist, you can imbue the stone with pure magical force to drop a meteorite swarm on an enemy's head)
For sheer scale, I'm going to pull a direct example from WOW and Compare it, as the reigning champion of the 'Old Generation' to GW2's status as the Vanguard of the New Generation (Alongside The Secret World, which I'm also looking forward to). In WoW: Cataclysm, Deathwing, the 'So evil, he shits pure hate' Big-Bad-Evil-Woe-Unto-The-World-As-Long-As-He-Lives-Dragon-Boss-Guy, has, as approximate scale, a wingspan of ~Roughly~ 1200 feet. (Citation here: http://www.wowpedia.org/Deathwing#Trivia
In GW2, The Shatterer, one of the ~lesser~ Generals of the Elder Dragon Kralkatorrik, is, approximately, half again Deathwing's size. (Of Trivia is that 'Shatterer' as a name, is merely the rank and title; once one dies, another dragon is given the position and name) Some short animated images of its usual entry to the battlefield, and 'wake up' call should help.
This is an enemy that's considered a major threat for level 45-50 players; the true Elder Dragons of Tyria are so physically immense and alien to comprehension that trying to describe one does not truly work. However, as a sense of scale, Kralkatorrik, when its awakening was described in the novel 'Edge of Destiny', had been, for centuries, mistaken as a medium-size mountain.
See those little white sails in the left corner? Those are what we now call 'tall ships' Brigandines, Frigates, and Ships of the line, essentially. Yeah. Big is an understatement.
Another feature GW2 has that most Fantasy MMOs do not is the abolition of 'Fantasy Gun Control' Every Race, and nearly every class can whip a pistol or rifle out of their backpack or robes and take potshots at an enemy. The classes that can not, or do not use firearms, are, in general, either stupidly powerful at range already (Elementalist), or use weapons that are easier to maintain when exploring the wild areas of the world (Ranger).
Also, how often do you go through a dungeon in most MMOs and end up paying around half of your hard-earned profits into basic repairs for your gear? GW2 still has gear maintenance, though in a way that'll make you smile; every time you're Defeated in battle (not just 'downed' which is where you can get back up if you kill your foe, or bandage your wounds), a piece of armour gets damaged; only after all five pieces of armour you can wear are damaged does one break and need to be repaired to restore function; So, you have five 'lives' before anything breaks, and it's only a handful of copper coins to get it back up to original, if well-worn, condition.
Now, I'm just running the bulletpoints by really quickly, and there's a massive pile of extra information out there, but this piece of information should probably be the most important. Like Guild Wars, Guild Wars 2 does NOT Require a Subscription fee.
Once you buy the box in a store, or online, that copy of the game is yours, and you play as much or as little as you like.
Personally, I spent 230$ on Guild Wars; 50$ for a regular edition of the original campaign, 70$ each for the CE of Factions and Nightfall, and 40$ on Eye of the North. I have played just under 11,000 Hours over 7 years. Doing the math, I have spent roughly 0.02$ per hour to play Guild Wars. For WoW, assuming you bought all the expansions, and played for the same amount of time over 7 years, you will have invested a total of 240$ into the games itself, and 1260$ for subscription fees. Broken down to cost-per-hour, if you play WoW for 11,000 hours over 7 years, the 1500$ investment you made breaks down to just over 0.135$/hour. (Note: This mathematical breakdown conveniently ignores things like ISP bandwidth usage for the purpose of removing extra variables) So, economically? I think I'll toss my hat into GW's ring once more. I like it over here, where I don't pay 15$ a month to play something I bought.
Edit; For a much-more informative summary of just how much GW2 is looking to upend the table of modern MMOs, read the OP of this thread. http://forums.somethingawful.com/showthread.php?threadid=3455607&userid=0&perpage=40&pagenumber=1
It has links to all the original information, and breaks it down into easy-to-digest chunks.